U.S. patent number 6,811,382 [Application Number 09/970,337] was granted by the patent office on 2004-11-02 for integrated pumping system for use in pumping a variety of fluids.
This patent grant is currently assigned to Schlumberger Technology Corporation. Invention is credited to Grigory L. Arauz, Steven E. Buchanan, Kenneth L. Havlinek, Ashley Kishino, Lawrence C. Lee, W. Keith Russell, Anthony F. Veneruso, Thomas H. Zimmerman.
United States Patent |
6,811,382 |
Buchanan , et al. |
November 2, 2004 |
Integrated pumping system for use in pumping a variety of
fluids
Abstract
An integrated pumping system for use in environments, such as
subterranean environments, to move a desired fluid from one
location to another. The integrated pumping system comprises one or
more stages that each have an integrated pump and motor. A
controller may be utilized to individually control the one or more
integrated pumps and motors.
Inventors: |
Buchanan; Steven E. (Pearland,
TX), Arauz; Grigory L. (Missouri City, TX), Havlinek;
Kenneth L. (Houston, TX), Kishino; Ashley (Houston,
TX), Lee; Lawrence C. (Pearland, TX), Russell; W.
Keith (Sugar Land, TX), Zimmerman; Thomas H. (Katy,
TX), Veneruso; Anthony F. (Missouri City, TX) |
Assignee: |
Schlumberger Technology
Corporation (Sugar Land, TX)
|
Family
ID: |
27399483 |
Appl.
No.: |
09/970,337 |
Filed: |
October 3, 2001 |
Current U.S.
Class: |
417/244;
415/199.1; 417/423.5; 417/426; 417/63 |
Current CPC
Class: |
E21B
43/128 (20130101); F04C 13/008 (20130101); F04D
13/14 (20130101); F04D 15/029 (20130101); H02K
19/103 (20130101); H02K 21/24 (20130101); H02K
7/14 (20130101); H02K 5/132 (20130101); H02K
16/00 (20130101) |
Current International
Class: |
E21B
43/12 (20060101); F04C 13/00 (20060101); F04D
13/14 (20060101); F04D 15/02 (20060101); F04D
13/00 (20060101); H02K 21/12 (20060101); H02K
19/02 (20060101); H02K 19/10 (20060101); H02K
21/24 (20060101); H02K 5/132 (20060101); H02K
5/12 (20060101); H02K 7/14 (20060101); H02K
16/00 (20060101); F04D 029/44 (); F04B 025/00 ();
F04B 035/04 (); F04B 041/06 () |
Field of
Search: |
;417/244,426,423.5,366,371,63 ;415/199.1,199.2,199.3 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Freay; Charles G.
Attorney, Agent or Firm: Van Someren, PC Griffin; Jeffrey E.
Echols; Brigitte Jeffery
Parent Case Text
This application claims priority under 35 U.S.C. .sctn. 119(e) to
U.S. Provisional Application Ser. No. 60/241,453 filed Oct. 18, 200
and to U.S. Provisional Application Ser. No. 60/305,312 filed Jul.
13, 2001.
Claims
What is claimed is:
1. An integrated pumping system, comprising: a plurality of stages
sequentially connected, each stage comprising a diffuser, a drive
motor and an impeller, wherein one or more of the plurality of
stages acts as a flow control valve to decrease a flow of
fluid.
2. The integrated pumping system as recited in claim 1, wherein
each stage of the plurality of stages is independently
controllable.
3. The integrated pumping system as recited in claim 1, wherein
each stage of the plurality of stages are independently
controllable to maintain operation of an operable stage if one or
more other stages fail.
4. The integrated pumping system as recited in claim 1, wherein the
impeller of each stage may be rotated at a unique speed relative to
impellers of other stages of the plurality of stages.
5. The integrated pumping system as recited in claim 2, further
comprising a control module coupled to each stage.
6. The integrated pumping system as recited in claim 5, wherein the
control module is retrievable independent of the plurality of
stages.
7. The integrated pumping system as recited in claim 1, further
comprising a bus to provide power to the plurality of stages.
8. The integrated pumping system as recited in claim 1, further
comprising a plurality of individual conductors to provide power to
the plurality of stages.
9. An integrated pumping system, comprising: a plurality of stages
sequentially connected, each stage comprising a diffuser, a drive
motor and an impeller, further comprising a electrical
quick-connect disposed between at least two of the stages.
10. An integrated pumping system, comprising: a plurality of stages
sequentially connected, each stage comprising a diffuser, a drive
motor and an impeller, wherein each stage of the plurality of
stages comprises a stage identifier to provide information to a
control module regarding at least one parameter of the stage.
11. The integrated pumping system as recited in claim 10, wherein
the stage identifier comprises a bar code.
12. The integrated pumping system as recited in claim 10, wherein
the stage identifier comprises a series of magnets.
13. The integrated pumping system as recited in claim 10, wherein
the stage identifier comprises a mechanism configured to provide an
electronically encoded signal in a time sequence with other
stages.
14. The integrated pumping system as recited in claim 10, wherein
the mechanism comprises a series of notches on each impeller.
15. The integrated pumping system as recited in claim 10, wherein
each stage further comprises a parameter sensor.
16. The integrated pumping system as recited in claim 15, wherein
the parameter sensor comprises a speed sensor.
17. The integrated pumping system as recited in claim 15, wherein
the parameter sensor comprises a temperature sensor.
18. The integrated pumping system as recited in claim 15, wherein
the parameter sensor comprises a vibration sensor.
19. The integrated pumping system as recited in claim 10, wherein
the drive motor comprises an induction motor.
20. The integrated pumping system as recited in claim 10, wherein
the drive motor is free of lubricating oil.
21. A pumping system, comprising: an outer housing; and a plurality
of internal impellers, wherein rotation of each of the internal
impellers is independently controlled, wherein each impeller
comprises an identifier that can be recognized by a controller as
an indication of one or more operating parameters.
22. The pumping system as recited in claim 21, further comprising a
plurality of internal motors, wherein each motor is integrated with
a corresponding internal impeller.
23. The pumping system as recited in claim 22, wherein the
plurality of internal motors are independently controlled by a
controller.
24. The pumping system as recited in claim 22, wherein the
plurality of internal motors comprise induction motors.
25. A system for moving a fluid, comprising: a pumping system
having a plurality of stages, each stage comprising a drive motor
having an internal flow path to receive a produced fluid
therethrough, an impeller, and an identifier associated with the
impeller that can be recognized by a controller as an indication of
one or more operating parameters.
26. The system as recited in claim 25, wherein each stage comprises
a diffuser.
27. The system as recited in claim 26, wherein the impeller of at
least one of the stages may be rotated at a speed different from
other impellers.
28. The system as recited in claim 25, wherein each stage of the
plurality of stages is independently controllable.
29. The system as recited in claim 25, wherein the drive motor
comprises an induction motor.
Description
FIELD OF THE INVENTION
The present invention relates generally to the pumping of fluids,
and particularly to the integration of a pump and electric motor to
facilitate various aspects of moving fluid from one location to
another.
BACKGROUND OF THE INVENTION
In a variety of pumping systems, such as electric submersible
pumping systems utilized in the production of subterranean fluids,
a distinct motor is used to drive a distinct and separate pump. In
electric submersible pumping systems, a motor is coupled to a motor
protector and ultimately to a submersible pump, such as a
centrifugal pump. The motor protector separates the internal motor
fluid from deleterious wellbore fluids, and the pump is driven by a
shaft coupled to the electric motor. A variety of other components
can be combined with the electric submersible pumping system for a
range of applications and environments.
SUMMARY OF THE INVENTION
The present invention provides a technique for integrating the
electric motor and the pump in various pumping systems. This
combination permits the elimination of the separate motor, motor
protector and other components while allowing greater control over
movement of fluid as well as improved flexibility of design.
Although the technique has particular application to systems used
in subterranean environments, such as electric submersible pumping
systems, the technique may be utilized in a variety of other
pumping applications.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will hereafter be described with reference to the
accompanying drawings, wherein like reference numerals denote like
elements, and:
FIG. 1 is a front elevational view of an exemplary application of
the present technique in a downhole, electric submersible pumping
system;
FIG. 2 is a front elevational view of the integrated motor and pump
illustrated in FIG. 1;
FIG. 3 is an alternate embodiment of the system illustrated in FIG.
2;
FIG. 4 is an exemplary electrical system utilized in controlling a
plurality of stages in the integrated pumping system of FIG. 2;
FIG. 5 is an alternate embodiment of the system illustrated in FIG.
4;
FIG. 6 is another alternate embodiment of the system illustrated in
FIG. 4;
FIG. 7 is another alternate embodiment of the system illustrated in
FIG. 4;
FIG. 8 illustrates exemplary mechanical and electrical quick
connects for coupling adjacent stages to each other;
FIG. 9 is a front elevational view of an integrated pumping system
and surface-based control system;
FIG. 9A is a schematic drawing of one exemplary stage sensor
system;
FIG. 9B illustrates an alternate arrangement of the stages of the
integrated motor and pump;
FIG. 10 is a cross-sectional view taken generally along the axis of
a stage of the integrated motor and pump, according to one
embodiment of the present invention;
FIG. 11 is a cross-sectional view taken generally along the axis of
an exemplary stage;
FIG. 12 is a cross-sectional view taken generally along the axis of
an alternative embodiment of an exemplary stage;
FIG. 13 is a top view of exemplary stator electromagnets
illustrated in FIG. 12;
FIG. 14 is a bottom view of exemplary rotor permanent magnets
illustrated in FIG. 12;
FIG. 15 is a schematic illustration of the stage illustrated in
FIG. 12 designed without mechanical constraint on the motion of the
rotor;
FIG. 16 is a cross-sectional view taken generally along the axis of
an exemplary stage utilizing an alternate motor embodiment;
FIG. 17 is a top view of the stator illustrated in FIG. 16;
FIG. 18 is a schematic illustration of an exemplary solenoid gap
profile; and
FIG. 19 is a schematic view of an alternate solenoid gap
profile.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring generally to FIG. 1, an integrated pumping system 10, is
illustrated in a subterranean environment according to one
embodiment of the present invention. In this embodiment, integrated
system 10 is part of an overall electric submersible pumping system
12 deployed for producing certain production fluids 14, such as
hydrocarbon-based fluids.
Integrated system 10 is deployed within a geological formation 16
for production of fluids from a well 18 via a wellbore 20 formed in
the geological formation 16. Typically, wellbore 20 is lined with a
wellbore casing 22 having an opening 24, e.g. perforations, through
which wellbore fluids enter wellbore 20 from geological formation
16. After fluids 14 enter wellbore 20, they are drawn through a
fluid intake 26 by integrated system 10 and produced to a desired
location, such as a holding tank at a surface 28 of the earth.
In the embodiment illustrated, integrated system 10 is coupled to a
deployment system 30 by a connector 32. Deployment system 30 may
comprise a variety of configurations, such as cable, coiled tubing
and production tubing. In FIG. 1, deployment system 30 comprises a
tubing 34 through which wellbore fluids are produced. (In other
designs, however, fluids are produced through the annulus formed in
the wellbore around deployment system 30.) Tubing 34 is suspended
from a wellhead 36 disposed, for example, proximate surface 28.
Power is provided to integrated system 10 via a power cable 38.
As illustrated in FIG. 2, integrated system 10 comprises at least
one stage 40 and typically a plurality of stages 40. The number and
arrangement of stages can vary significantly from one application
to another depending on the production environment, depth, fluid
parameters and a variety of other design considerations. In the
exemplary embodiment, each stage generally is divided into an
impeller section 42, a motor section 44 and a diffuser section
46.
The plurality of stages 40 cooperate to move the desired production
fluid 14. As fluid 14 is drawn through intake 26 into the first
stage 40, the first diffuser 46 directs the fluid through
appropriate channels in motor section 44 to impeller section 42.
The impeller section 42 is rotated to propel fluid 14 to the next
subsequent stage which moves the fluid to the next stage until
ultimately the fluid is discharged into, for example, tubing 34. As
will be explained more fully below, this integrated design allows
for elimination of the drive shaft that would otherwise couple an
electric motor to a separate pump. The design also eliminates the
need for internal motor oil as well as elastomers, such as seals
used to prevent loss of or contamination of the motor oil.
It should be noted that motor sections 44 can be utilized and
controlled independently to rotate the various impellers at
differing speeds or even in different directions as discussed in
greater detail below. The use of integrated motor and pump sections
allows for great flexibility of use and control over the pumping of
fluid 14. In some designs, the individual stages 40 are configured
as modular units that may be readily separated and recombined in a
variety of arrangements and with a variety of components disposed
therebetween (see FIG. 3).
In the embodiment of FIG. 3, a plurality of stages 40 are separated
by various components. For example, a plurality of lower stages are
coupled to an integrated intake 48 that allows the stages to draw
fluid into integrated system 10 from a first zone 50 and discharge
the fluid downwardly through a discharge end 52. Simultaneously, a
plurality of upper stages 40 are coupled to a second intake 54
positioned to draw fluid from an upper zone 56. The fluid drawn
from zone 56 is produced upwardly through connector 32 and tubing
34. In this embodiment, a fluid separator 58 is disposed between
intakes 48 and 54. Furthermore, a variety of other components, such
as an instrumentation component 60, may be disposed between various
stages 40. The embodiment illustrated in FIG. 3 is just one example
of a wide variety of configurations facilitated by a modular design
of stages 40 and overall integrated system 10.
To independently control the stages 40, a variety of control
systems can be used, as illustrated in FIGS. 4 through 7.
Generally, the exemplary techniques for providing power to stages
40 permit isolation of stages from other stages so that failure of
one or more stages does not affect the others.
In the example illustrated in FIG. 4, a control module 62 is
coupled both to power cable 38 and to each stage 40, e.g. stages 1,
2 and 3, by a separate conductor 64. Control module 62 may be
designed to convert the electrical input from series to parallel to
permit individual control of the stages. Furthermore, conductor 64
may be deployed as independent electrical cables, such as each
cable from the surface and without a control module 62, or as a bus
running through integrated system 10.
Control module 62 typically is designed to electrically isolate
each stage from the other stages such that when one stage fails,
the remaining stages may be powered and operated. Additionally,
control module 62 may be designed as a retrievable module deployed
and retrieved through tubing 34. In lieu of control module 62,
individual cables can be run from the surface to each of the
stages. However, many applications benefit from the ability to use
a single power cable 38 combined with control module 62 to
separately control the relay of power to each of the individual
stages 40.
In an alternate embodiment, illustrated in FIG. 5, a series scheme
can be utilized to power stages 40. In this design, stages 40 are
electrically connected in series by a plurality of conductor
segments 66. Each stage 40 is electrically isolated by an isolation
device 68, such as a fuse or automatic switch. Thus, when one stage
40 fails, only the stages below it (as referenced in FIG. 5) are
electrically separated from power cable 38. The stages above the
failed stage remain in operation.
In another alternate embodiment, illustrated in FIG. 6, a ladder
scheme is utilized to provide power to the various stages 40. In
this embodiment, a pair of primary conductors 70 are coupled to
each stage by a pair of electrical couplings 72. The primary
conductor 70 may comprise cables, such as power cables run from the
surface. Each stage 40 is connected in parallel to both primary
conductors 70 such that if the connection between one of the
primary conductors and one of the stages fails, that same stage
remains functional by virtue of its connection to the other primary
conductor 70. Isolation devices 74, such as fuses, also can be
utilized between each stage and each primary conductor 70.
Another embodiment, illustrated in FIG. 7, comprises a ring scheme,
which is similar to the series scheme illustrated in FIG. 5 with an
additional power cable 38. One power cable 38 is coupled to the
uppermost stage 40, while the other power cable 38 is coupled to
the lowermost stage 40. Each of the stages are electrically coupled
to each other by appropriate conductor segments 76. Also, an
isolation device 78, such as a fuse, is deployed between each
consecutive stage. When a stage fails, the surrounding devices 78
operate to isolate the failed stage, while the power cable 38
coupled to the uppermost stage provides power to stages above the
failed stage and the power cable 38 coupled to the lowermost stage
provides power to the stages below the failed stage. Other
arrangements also can used to provide power to individual stages of
integrated system 10, such as multiple independent cables or
bundled cables with a specific cable designated for each stage.
In the designs described above, it may be advantageous to utilize a
bus or other systems that allow the use of electrical
quick-connects so that separate modules can easily be connected and
separated either in the factory or at the well site. Such
electrical quick-connects work well with mechanical connection
methods, such as mating flanges or threaded collars configured to
mechanically join one stage to another.
For example, in FIG. 8, a mating flange engagement system is
illustrated. In this embodiment, one stage 40 is coupled to a
sequential stage 40 by a flange connector 73. Flange connector 73
comprises a flange 73A attached to one end of a given stage 40.
Flange 73A is designed for abutting engagement with a corresponding
connector end 73B of the next adjacent stage 40. Typically, flange
end 73A is fastened to connector end 73B by appropriate fasteners,
such as bolts 75 that extend through flange end 73A for threaded
engagement with connector end 73B. This arrangement permits the
quick connection and disconnection of each stage 40 from its next
adjacent stage 40.
Additionally, the system may be designed with appropriate
electrical quick-connects 77. The exemplary quick-connects 77 each
comprise a male end 77A disposed at the connection end of one of
the stages 40 and a female connection end 77B disposed on the
corresponding connection end of the next adjacent stage 40. Female
ends 77B are arranged to receive male ends 77A when flange end 73A
is coupled to connector end 73B. If, for example, the power
conductors are routed through sequential stages 40, quick-connects
77 allow rapid connection and disconnection of the conductors
during assembly and disassembly adjacent stages.
A variety of controllers, such as the downhole control module 62
illustrated in FIG. 4 or a surface control module 83 illustrated in
FIG. 9, can facilitate the flexibility and adaptability of
integrated system 10. A controller, e.g. control module 62 or
surface controller 83, is utilized to automatically redistribute
power when one stage 40 fails. In fact, potentially greater power
can be provided to the remaining stages to maintain a comparable
level of fluid production. The controller also can be used to
determine when a failure has occurred and/or to take corrective
action to compensate for the failure. Exemplary actions that may
compensate for failure of a stage are increasing current to
remaining stages or increasing the speed of some or all of the
remaining stages.
If a controller is combined with the integrated pump system, each
stage typically includes a mechanism by which it is identified to
the controller, e.g. a stage identifier 81 (see FIG. 9A). This
allows the controller to determine whether a problem exists at a
particular stage and/or the proper action to correct or compensate
for the problem. Additionally or in the alternate, each stage can
provide an appropriate output to a controller interface, such as a
display screen, for analysis by an operator.
There are a variety of mechanisms that can be used as stage
identifiers 81 for identifying the operation of each stage, such as
bar codes disposed on movable components, e.g. impellers 42.
Another type of stage identifier 81 comprises a series of magnets
arranged on a movable component of each stage to create a specific
signature when sensed by an inductive sensor. Another exemplary
stage identifier 81 comprises configuring individual stages to
provide an electronically encoded signal in a time sequence with
the other stages, e.g. based on rotation of the impeller. For
example, a given impeller 42 (or other part of the rotor) can be
fabricated with a plurality of notches or other features,
represented by stage identifiers 81 in FIG. 9A. The notches are
detected by a proximity sensor 85 that outputs a signal to an
analyzer 87. The signal is representative of the pattern of notches
and is used to create a unique time domain signature 89.
With any of these mechanisms, the signal or signals output to the
controller will change upon failure of one or more of the monitored
stages. This allows the controller or an operator to compensate for
the failed stage or stages. If the controller is located remotely,
such as surface controller 83, the output signals can be
transmitted through power cable 38. The ability to identify and
control individual stages provides an operator great flexibility in
operating the pumping system. For example, the operator is able to
identify problems in individual stages and to address those
problems by controlling the individual stages independently of the
other stages.
If desired, other types of sensors can be combined with the
individual stages 40 or located proximate integrated system 10. For
example, speed sensors can be used with each stage to sense the
frequency of rotation and corresponding signals can be output to a
controller, e.g. surface controller 83, to provide frequency
signatures for each of the stages. Additionally, vibration sensors
may be coupled to or incorporated with each stage to sense
vibration and output appropriate signals representative of
vibration signatures. The signatures are monitored and analyzed by
an appropriate controller or operator. Other sensors, such as
temperature sensors, pressure sensors, flow sensors etc. may be
embedded in one or more stages to sense various parameters and
output corresponding signals for analysis and use in evaluating the
operation of integrated system 10. Each of the sensed parameters
can be utilized to collectively or individually control the various
stages to optimize performance of the system. This individual
control also allows individual stages or groups of stages to be
used as flow control valves.
The flexibility of control permits adaptation of integrated system
10 to many environments. For example, individual stages 40 may be
used as flow control valves. When one or more stages are producing
from different formations, such as formations A, B and C of FIG.
9B, an operator is able to independently control the stages and
hence the flow associated with different formations. The operator
simply may turn individual stages or groups of stages on or off to
select different production parameters for each formation. This can
be advantageous when used for well testing where formations are
flowed intermittently or for limiting the effects of coning of
fluid from one formation to another. The production speed of each
stage or group of stages also can be adjusted based on factors such
as gas production, component wear, erosion, etc.
The flexible modular design, as shown in FIG. 3, also allows the
use of a variety of other completion elements, such as multiple
intakes 48, separator 58, instrumentation component 60, sleeves,
generators, flow control valves, test equipment, gas handlers and a
variety of other completion components that can be incorporated
into a wide range of completion configurations between, above or
below the stages. Because electrical power conductors are run along
or through the stages, the various other components can be powered
without running a separate electrical power cable. Power also can
be provided by generators or energy storage units, e.g. batteries,
deployed in the completion. For example, instrumentation component
60 may be substituted or supplemented with an electrical generator
or battery integrated with system 10. With these potential sources
of electric power, internal batteries may not be required for
certain testing equipment and hydraulic control lines potentially
can be eliminated by switching to electrically actuated
components.
The system flexibility also can be supplemented by the ability to
use external sensors, such as a sensor 84 illustrated in FIG. 9B.
In one exemplary embodiment, sensor 84 is attached to casing 22 and
the adjacent stage or stages 40 are coupled to sensor 84 by an
electromagnetic coupler 86. In this manner, sensor or sensors 84
can be activated automatically when the integrated system 10 is
deployed downhole and an electrical connection is formed via
coupler 86. When the stages are retrieved from the downhole
environment, the electromagnetic coupling is broken leaving the
sensor or sensors 84 in the downhole environment.
Because no shaft is required and the stages may be independently
powered, adjacent pump stages can be rotated in opposite directions
or at differing speeds. In some applications, rotation of certain
stages in opposite directions may improve the torque balance of the
overall completion. The counter rotating stages also may diminish
undesirable swirling in the production fluid. Apart from pumping in
a single direction, the stages readily may be designed to pump
fluids in opposite directions (see FIG. 3). For example, if a
separator is deployed between stages, the upper stages 40 can be
used to pump the separated oil upwardly to the surface while the
lower stages 40 are used to pump the separated fluid downwardly to,
for example, a dump formation.
Referring generally to FIG. 10, an embodiment of a typical stage 40
is illustrated. Motor section 44 comprises a drive motor 90 that is
coupled to and able to rotate an impeller 92 disposed in impeller
section 42. Drive motor 90 has an integral fluid flow path 94 into
which fluid is drawn from a diffuser 96 disposed in diffuser
section 46. Fluid is drawn through diffuser flow passages 98 along
flow path 94, through motor section 44 and into a plurality of
impeller vanes 100. As impeller 92 rotates, the fluid is forcibly
discharged from impeller vanes 100 to the next succeeding stage 40
or out of integrated system 10.
Impeller 92 may be supported by a thrust bearing 102. Additionally,
the various internal stage components are enclosed within an outer
housing 104 having an upper end 106 and a lower end 108. If stages
40 are designed as modular stages, housing ends 106 and 108 are
configured as mounting ends that may be selectively coupled and
uncoupled from adjacent components. It also should be noted that
the arrangement of components within each stage may be modified.
For example, the modular stages may be designed with the diffuser
in the upper position, and the impeller disposed between the
diffuser and the drive motor.
One embodiment of drive motor 90 is illustrated in FIG. 11. In this
embodiment, drive motor 90 comprises a cylindrical rotor motor,
such as an ac induction motor. However, drive motor 90 also may
comprise other types of motors, such as a reluctance motor, a
permanent magnet synchronous motor or a DC motor. The exemplary
motor illustrated comprises a motor rotor 110 having a longitudinal
flow path 112 therethrough. Rotor 110 is supported by a thrust
bearing 114 on a bottom end and is coupled to impeller 92 at an
upper end. In this particular embodiment, diffuser 96 is disposed
above impeller 92 within the stage 40. However, the stage may
readily be designed to accommodate diffuser 96 beneath drive motor
90, as illustrated in FIG. 10. Similarly, thrust bearing 114 may be
located beneath impeller 92, as illustrated in FIG. 10. Rotor 110
is surrounded by a stator 116 having a plurality of stator windings
utilized to impart rotation to rotor 110, as known to those of
ordinary skill in the art.
In this embodiment, as well as other embodiments of drive motor 90,
a variety of internal sensors, e.g. sensors 111A and 111B, can be
utilized in sensing fluid and/or motor related parameters. For
example, sensor 111A may be located proximate impeller 92 to sense
speed or vibration. Another exemplary sensor, such as sensor 111B,
can be positioned in a variety of locations to sense temperature.
The sensors output signals to an appropriate monitor or
controller.
Another exemplary drive motor 90 is a permanent magnet motor 118,
as illustrated in FIGS. 12 through 14. In this embodiment, a rotor
120 is rotatably disposed above a stator 122. Rotor 120 comprises a
plurality of downwardly facing permanent magnets 124, as
illustrated in FIGS. 12 and 14. Permanent magnets 124 cooperate
with a plurality of electromagnets 126 disposed in stator 122 and
oriented to face permanent magnets 124, as illustrated in FIGS. 12
and 13. Sequential energization of electromagnets 126 imparts
rotational motion to rotor 120 and impeller 92 which is connected
to or formed as part of rotor 120. As with the previous designs
discussed, fluid is drawn upwardly through diffuser 96, stator 122
and rotor 120 along a flow path referenced as flow path 128(see
FIG. 12).
A variety of bearings, such as a radial bearing 130, may be
utilized to limit the degrees of freedom that rotor 120 and
impeller 92 are allowed to move. However, this type of motor does
permit the elimination of one or more of these bearing or wear
surfaces by controlling the positioning of rotor 120 and impeller
92 through electromagnetic forces rather than mechanical restraint
(see FIG. 15).
By properly aligning the poles the of the magnets and by providing
current to the electromagnets, the rotor 120/impeller 92 is
levitated by a repulsive force. The impeller can then be rotated by
selective energization of electromagnets 126. If additional degrees
of freedom are controlled electromagnetically, a plurality of
sensors typically are incorporated into the stage to measure the
position of the rotor relative to the electromagnets. The sensors
can be positioned to determine, for example, axial distance between
the electromagnets and the rotor as well as radial displacement of
the rotor. The signals from the sensors are output to a controller
that adjusts the energization of electromagnets 126 to control the
positioning and rotational speed of rotor 120/impeller 92.
Depending on whether physical bearings are utilized and the desired
level of control over impeller 92, no sensors or multiple sensors
may be used to detect impeller position. In a physically
constrained system, e.g. the system illustrated in FIG. 12, sensors
can be avoided in an open loop system. However, sensors often are
utilized to detect parameters such as speed of rotation and/or
levitation of the impeller. In unconstrained systems, e.g. the
system illustrated in FIG. 15, additional sensors may be used to
accurately detect positions of the impeller along multiple degrees
of freedom. For example, six sensors could be utilized to detect
movement in any of the six degrees of freedom. Other sensors, such
as temperature and pressure sensors, also can be incorporated into
the design.
Another exemplary embodiment of an integrated pump and motor is
illustrated in FIGS. 16 through 19. In this embodiment, a solenoid
drive motor utilizes generally C-shaped solenoids 130 that
cooperate with a skirt 132. Solenoids 130 comprise windings 133,
e.g. copper windings, disposed proximate a recessed or air gap area
134 sized to receive skirt 132. Skirt 132 comprises alternating
ferritic sections 135 and non-ferritic sections 135A, as
illustrated schematically in FIG. 17. By sequentially energizing
the windings 133 of solenoids 130, the resultant magnetic
attraction or repulsion acts on the alternating ferritic sections
to rotate skirt 132 along recessed section 134.
As illustrated, skirt 132 is coupled to impeller 92 to provide
impeller rotation. When the impeller is rotated, fluid is drawn
along a fluid flow path 136 through diffuser 96, drive motor 90 and
impeller 92 which discharges the fluid to the next sequential
component. In this design, impeller 92 may be held for rotation
about its axis by appropriate bearings, such as a radial bearing
138. Additionally, permanent magnets 140 may be disposed at a lower
portion of impeller 92 and an upper portion of diffuser 96 to
provide a separation force or repelling force between the impeller
92 and diffuser 96. This repellant force facilitates separation of
the components during operation of the stage.
In a typical application, the legs of the C-shaped solenoids 130
are generally rectangular in cross-section, as illustrated in FIGS.
17 and 18. By appropriately interrupting current to the solenoids
on a periodic basis, the ferritic sections of skirt 132 are moved
along recess 134 in a rotating manner, as known to those of
ordinary skill in the art. However, the need to interrupt the
current can be obviated by changing the rectangular profiles of the
C-shaped solenoids to divergent portions 144, as illustrated in
FIG. 19. Each divergent portion 144 is constructed with a lead edge
disposed closer to skirt 132 than its trailing edge to create the
divergent profiles. In the specific embodiment illustrated, each
portion 144 is broader in cross section at its lead end and
narrower at its trailing end. As a ferritic section 135 of skirt
132 is drawn through divergent sections 144, the divergence
sufficiently reduces the electromagnetic force of the solenoid 130
such that the ferritic section passes through divergent portion
144, allowing skirt 132 and impeller 92 to continue rotating. It
should be noted, however, that a wide variety of drive motor
configurations, impeller configurations, diffuser configurations
and arrangements of components can be used in constructing stages
40 without departing from the scope of the invention.
In each of the exemplary embodiments, the integrated motor and pump
allows for the elimination of various components necessary in
conventional electric submersible pumping systems. For example, no
shaft is required to couple a submersible motor to a separate
submersible pump. Additionally, no internal motor oil is required
which not only eliminates the need for motor oil but also for
various elastomers, such as seals, e.g. shaft seals. The lack of
motor oil also obviates the need for a motor protector disposed
intermediate a submersible motor and a separate submersible
pump.
Overall, it should be understood that the foregoing description is
of exemplary embodiments of this invention, and that the invention
is not limited to the specific forms shown. For example, the use of
integrated motor and pump stages can be used in a variety of
applications other than downhole applications; the independent
stages may be combined in a unitary structure or constructed in
modules that are readily connected with other stage modules as well
as other types of components; the various control systems may vary
based on environment, components utilized in the integrated system
and the type of drive motor utilized; and the number and size of
stages and other components can be adapted to various applications.
Also, the specific design of each stage may vary or be adapted to
new pump, motor and material technologies. These and other
modifications may be made in the design and arrangement of the
elements without departing from the scope of the invention as
expressed in the appended claims.
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